Professor Jeff McMahan has been a vegetarian for 50 years but is still querying the ethics of eating meat.

He explained to Faima Bakar why it may actually be beneficial for animals if they are reared to be killed.

'Might we benefit animals by eating them?'

It seems like a strange question for a committed vegetarian to ask, but that is exactly the quandary one Oxford academic is trying to solve.

Professor Jeff McMahan recently delivered a lecture on the topic, asking whether it can be good for animals to be brought into the world even if they are reared to be killed and eaten.

The professor of moral philosophy at Oxford University, who has been a vegetarian for 50 years, said he was in a dilemma over whether the act of killing an animal and eating it can be justified by providing it with an enjoyable life in the first place.

He examines the argument that some species of animal would not exist at all if they were not reared for food.

He said: "Could it be permissible to eat meat only from animals that have been raised in humane conditions, in which they are not caused to suffer, and are killed with as little pain and fear as possible?"

Although the philosopher now has a moral problem with eating meat things were rather different when he was a young man and hunted animals in his home in South Carolina, United States.

He said: "Because I lived in the country and had to eat what my parents gave me because there was no store within many miles of where I lived, I could not become a vegetarian until I left for university."

His wife, and two children are also vegetarian, something they chose after trying meat in their childhood.

The basis of the lectures stems from a statement made by the English author and father of Virginia Wolf, Leslie Stephen, who wrote: “The pig has a stronger interest than anyone in the demand for bacon.

"If all the world were Jewish, there would be no pigs at all”.

"As I understand it, the point is that a practice that involves causing animals to exist, giving them lives worth living, and then killing them prematurely is on balance good for them."

In his lecture, Prof McMahan says: "We think of killing animals as a harm, but it doesn't actually cause the victim anything intrinsically bad.

“Not eating meat just prevents people from having further benefits."

He often makes comparisons between killing human beings and animals.

He said: “The argument can be applied in the case of persons – we might create new people only on condition that we would be able to kill them at some point in adulthood and use their organs for donations and transplantation to save the lives of a great number of others.

"I don’t know anybody who would think that is permissible.”

No matter how often he asks the hypothetical questions, Prof McMahan still believes it is morally wrong to raise animals to be eaten, even if they are treated humanely.

He said: "After I gave the lecture I read an article by a man who had bought some piglets, raised them humanely, and then slaughtered them for food.

"Reading that reinforced my strong intuitive sense that humane omnivorism is wrong.

"But I am still trying to understand whether it really is wrong and why."